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If the locking collar is engaged and you have the locking screw loosened, it could be worth trying to release it first. (Screw anticlockwise) I just tried mine and when the collar is engaged it can be quite tight to then disengage. Try it with your spare, engaging and disengaging the locking collar does not affect the calibration.
Re lubricant the internet suggests clock oil for micrometers. (not silicone which creeps and could end up on the optics)
If the grub screw was not loose and the locking collar cannot be turned even after loosening the screw it is unlikely that this is the reason that the micrometer had become tight. (Did it suddenly become tight or has it becoming increasingly tight over time). Can you tell from my photos and comparing with the other LHIRES if the collar is engaged or disengaged ?
Other than that I guess it needs an overhaul, removing it, unscrewing the barrel cleaning and re-lubricating. Mine is still fine after 18 years though (I recall you have a remote adjustment, could this have been preloading it causing premature wear?)
Photos with the collar engaged and disengaged
I just used a Jeweller’s screwdriver but if the grub screw is tight then it seems unlikely that the collar has moved so it probably is not the reason for the micrometer becoming tight. With mine the locking collar is close to the spectrograph body when engaged and there is a definite gap with it disengaged. I will take a couple of photos.
Cheers
RobinThere is a knurled collar at the base of the micrometer held in position with a tiny cross head grub screw which is used to lock the micrometer at a given setting. Has that got tightened down? Mine is fully wound off (anticlockwise) and locked down with the grub screw.
Cheers
RobinMeanwhile ZTF have “discovered” their second high proper motion star in the past 3 months
https://www.wis-tns.org/object/2023acmv
https://www.wis-tns.org/object/2024dumRobin
That’s odd. According to time on the confirming spectrum on TNS, it was taken a day before the discovery date
Robin
Followed this up with the GOTO team. The date of the spectrum was indeed wrong and is now corrected in TNS
Robin
That’s odd. According to time on the confirming spectrum on TNS, it was taken a day before the discovery date
Robin
Stars with H alpha emission lines (of which there are several in the Pleiades) in a narrow band H alpha filter (where the solar spectrum has a deep absorption) might be interesting.
Hi Andy,
I don’t appear to have received any newsletters since no 72 last October. Are they archived anywhere ?
Cheers
RobinInteresting. I don’t think the comparison between the mass deorbited and the amount of material in the Van Allen belt is particularly helpful as the two are not comparable (We already receive ~ 40T/day of metals from meteorites) but at the future projected rate of 23 satellite deorbits a day (in the paper) the amount of additional material would appear to be comparable.
I have just been listening to one of the scientists involved in that study on BBC world service Science in Action
https://www.bbc.co.uk/sounds/play/w3ct4sdl
starting at 22:40Robin
There could be some financial advantage to extending the time over which power can be generated rather than increasing capacity on the ground. For a region heavily dependent on solar power, the price of night time electricity must presumably attract a high premium due to the high cost of storage or alternative generating capacity.
I don’t see any convincing arguments for using LED lights with a high blue spectral content for outdoor lighting and many reasons why it should not be used. Why any council lighting engineers should still be pushing back on this these days when alternatives with a lower blue content are available is beyond me
Here is his Mario Motta’s review from a US perspective.
https://www.mariomottamd.com/street-lighting/See a presentation on this at the 2018 joint BAA/AAVSO meeeting
https://britastro.org/event/baa-aavso-joint-meeting-on-variable-stars
Mario Motta – American Medical Association statement on street lighting
There could be a video of it somewhere on the website
I tried pointing out to the local lighting officer and my County Councillor that lower colour temperature LEDs were better, as they reduced scattered light in hazy/foggy conditions
You would probably have more success going on social media saying blue LED lighting causes cancer. (Unlike with 5G there is apparently some evidence to support this and has caused some towns in the US to rip out their recently installed blue LEDs in favour of lower temperature versions. See a presentation on this at the 2018 joint BAA/AAVSO meeeting). Failing this, pointing out the effect on wildlife might gain more traction among the general public, particularly if yo have any green councillors
Richard Berry is trying the Origin out for variable star photometry. There is the opportunity to use the green channel as with DSLRs, or all the light, depending on the goal of the observation.
The HOYS Citizen Science Project are accepting observations from ZWO Seestar 50mm telescopes, these use a colour CMOS chip. This is a research project run by Dirk Froebrich at the University of Kent, to monitor young stars.
Both of these approaches use the raw files saved by these smart-telescopes, rather than the processed images displayed on smartphones and tablets.
AndyThese ideas might attract people into scientific applications of their kit but these solutions are pretty suboptimal. It reminds me of the days of converting webcams for deep sky imaging. The results were impressive given the limitations of the kit but far from what came after based on the huge interest in imaging it generated. Hopefully the smart scope manufacturers might see there is a market for mono sensors which can take filters. ZWO should be perfectly placed to do this for example as their SeeStar uses the same CMOS sensor in colour version as another of their cameras which uses the mono version (There are apparently already people using Star Analyser on the front of this scope and even hacking into it to mount it internally, though the colour sensor is a big drawback)
There are other examples of areas where there is a tension between what is good for (marketing to) imagers and not for science. For example fancy mulit-coatings which make the difference between 95 and 98% are a disaster for short wavelength measurements.
